Practical Considerations for Single-Cell Genomics
Claire Regan
Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
Contribution: Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft
Search for more papers by this authorCorresponding Author
Jonathan Preall
Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
Corresponding author: [email protected]
Contribution: Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft
Search for more papers by this authorClaire Regan
Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
Contribution: Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft
Search for more papers by this authorCorresponding Author
Jonathan Preall
Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
Corresponding author: [email protected]
Contribution: Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft, Writing - original draft
Search for more papers by this authorPublished in the Molecular Biology section
Abstract
The single-cell revolution in the field of genomics is in full bloom, with clever new molecular biology tricks appearing regularly that allow researchers to explore new modalities or scale up their projects to millions of cells and beyond. Techniques abound to measure RNA expression, DNA alterations, protein abundance, chromatin accessibility, and more, all with single-cell resolution and often in combination. Despite such a rapidly changing technology landscape, there are several fundamental principles that are applicable to the majority of experimental workflows to help users avoid pitfalls and exploit the advantages of the chosen platform. In this overview article, we describe a variety of popular single-cell genomics technologies and address some common questions pertaining to study design, sample preparation, quality control, and sequencing strategy. As the majority of relevant publications currently revolve around single-cell RNA-seq, we will prioritize this genomics modality in our discussion. © 2022 Wiley Periodicals LLC.
CONFLICT OF INTEREST
The authors declare no conflict of interest.
Open Research
DATA AVAILABILITY STATEMENT
Data sharing is not applicable to this article, as no datasets were generated or analyzed during the study.
LITERATURE CITED
- Adam, M., Potter, A. S., & Potter, S. S. (2017). Psychrophilic proteases dramatically reduce single-cell RNA-seq artifacts: A molecular atlas of kidney development. Development, 144(19), 3625–3632. doi: 10.1242/dev.151142
- Aldridge, S., & Teichmann, S. A. (2020). Single cell transcriptomics comes of age. Nature Communications, 11(1), 4307. doi: 10.1038/s41467-020-18158-5
- Allaway, K. C., Gabitto, M. I., Wapinski, O., Saldi, G., Wang, C.-Y., Bandler, R. C., … Fishell, G. (2021). Genetic and epigenetic coordination of cortical interneuron development. Nature, 597(7878), 693–697. doi: 10.1038/s41586-021-03933-1
- Alles, J., Karaiskos, N., Praktiknjo, S. D., Grosswendt, S., Wahle, P., Ruffault, P.-L., … Rajewsky, N. (2017a). Cell fixation and preservation for droplet-based single-cell transcriptomics. BMC Biology, 15(1), 44. doi: 10.1186/s12915-017-0383-5
- Alles, J., Karaiskos, N., Praktiknjo, S. D., Grosswendt, S., Wahle, P., Ruffault, P.-L., … Rajewsky, N. (2017b). Cell fixation and preservation for droplet-based single-cell transcriptomics. BMC Biology, 15(1), 44. doi: 10.1186/s12915-017-0383-5
- Attar, M., Sharma, E., Li, S., Bryer, C., Cubitt, L., Broxholme, J., … Bowden, R. (2018). A practical solution for preserving single cells for RNA sequencing. Scientific Reports, 8(1), 2151. doi: 10.1038/s41598-018-20372-7
- Ayhan, F., Douglas, C., Lega, B. C., & Konopka, G. (2021). Nuclei isolation from surgically resected human hippocampus. STAR Protocols, 2(4), 100844. doi: 10.1016/j.xpro.2021.100844
- Bageritz, J., Krausse, N., Yousefian, S., Leible, S., Valentini, E., & Boutros, M. (2021). Glyoxal as alternative fixative for single cell RNA sequencing (preprint). Genomics, doi: 10.1101/2021.06.06.447272
- Bakken, T. E., Hodge, R. D., Miller, J. A., Yao, Z., Nguyen, T. N., Aevermann, B., … Tasic, B. (2018). Single-nucleus and single-cell transcriptomes compared in matched cortical cell types. PLoS ONE, 13(12), e0209648. doi: 10.1371/journal.pone.0209648
- Baslan, T., Kendall, J., Rodgers, L., Cox, H., Riggs, M., Stepansky, A., … Hicks, J. (2012). Genome-wide copy number analysis of single cells. Nature Protocols, 7(6), 1024–1041. doi: 10.1038/nprot.2012.039
- Broseus, L., & Ritchie, W. (2020). Challenges in detecting and quantifying intron retention from next generation sequencing data. Computational and Structural Biotechnology Journal, 18, 501–508. doi: 10.1016/j.csbj.2020.02.010
- Cao, J., Packer, J. S., Ramani, V., Cusanovich, D. A., Huynh, C., Daza, R., … Shendure, J. (2017). Comprehensive single cell transcriptional profiling of a multicellular organism. Science, 357(6352), 661–667. doi: 10.1126/science.aam8940
- Chen, D., Abu Zaid, M. I., Reiter, J. L., Czader, M., Wang, L., McGuire, P., … Liu, Y. (2021). Cryopreservation preserves cell-type composition and gene expression profiles in bone marrow aspirates from multiple myeloma patients. Frontiers in Genetics, 12, 583. doi: 10.3389/fgene.2021.663487
- Chen, H., Liao, Y., Zhang, G., Sun, Z., Yang, L., Fang, X., … Guo, G. (2021). High-throughput Microwell-seq 2.0 profiles massively multiplexed chemical perturbation. Cell Discovery, 7(1), 1–4. doi: 10.1038/s41421-021-00333-7
- Cheng, S., Pei, Y., He, L., Peng, G., Reinius, B., Tam, P. P. L., … Deng, Q. (2019). Single-cell RNA-Seq reveals cellular heterogeneity of pluripotency transition and x chromosome dynamics during early mouse development. Cell Reports, 26(10), 2593–2607.e3. doi: 10.1016/j.celrep.2019.02.031
- Chhangawala, S., Rudy, G., Mason, C. E., & Rosenfeld, J. A. (2015). The impact of read length on quantification of differentially expressed genes and splice junction detection. Genome Biology, 16(1), 131. doi: 10.1186/s13059-015-0697-y
- Consortium, T. T. S., & Quake, S. R. (2021). The Tabula Sapiens: A single cell transcriptomic atlas of multiple organs from individual human donors. Science, 376(6594), doi: 10.1126/science.abl4896
- Cusanovich, D. A., Daza, R., Adey, A., Pliner, H. A., Christiansen, L., Gunderson, K. L., … Shendure, J. (2015). Multiplex single-cell profiling of chromatin accessibility by combinatorial cellular indexing. Science, 348(6237), 910–914. doi: 10.1126/science.aab1601
- Daley, T., & Smith, A. D. (2013). Predicting the molecular complexity of sequencing libraries. Nature Methods, 10(4), 325–327. doi: 10.1038/nmeth.2375
- Dammer, E. B., Duong, D. M., Diner, I., Gearing, M., Feng, Y., Lah, J. J., … Seyfried, N. T. (2013). A neuron enriched nuclear proteome isolated from human brain. Journal of Proteome Research, 12(7), 3193–3206. doi: 10.1021/pr400246t
- De Rop, F. V., Ismail, J. N., Bravo González-Blas, C., Hulselmans, G. J., Flerin, C. C., Janssens, J., … Aerts, S. (2022). Hydrop enables droplet-based single-cell ATAC-seq and single-cell RNA-seq using dissolvable hydrogel beads. ELife, 11, e73971. doi: 10.7554/eLife.73971
- Deerhake, M. E., Reyes, E. Y., Xu-Vanpala, S., & Shinohara, M. L. (2021). Single-cell transcriptional heterogeneity of neutrophils during acute pulmonary Cryptococcus neoformans infection. Frontiers in Immunology, 12, 670574. doi: 10.3389/fimmu.2021.670574
- Del-Aguila, J. L., Li, Z., Dube, U., Mihindukulasuriya, K. A., Budde, J. P., Fernandez, M. V., … Harari, O. (2019). A single-nuclei RNA sequencing study of Mendelian and sporadic AD in the human brain. Alzheimer's Research & Therapy, 11(1), 71. doi: 10.1186/s13195-019-0524-x
- Delley, C. L., & Abate, A. R. (2021). Modular barcode beads for microfluidic single cell genomics. Scientific Reports, 11(1), 10857. doi: 10.1038/s41598-021-90255-x
- Denisenko, E., Guo, B. B., Jones, M., Hou, R., de Kock, L., Lassmann, T., … Forrest, A. R. R. (2020). Systematic assessment of tissue dissociation and storage biases in single-cell and single-nucleus RNA-seq workflows. Genome Biology, 21(1), 130. doi: 10.1186/s13059-020-02048-6
- Domcke, S., Hill, A. J., Daza, R. M., Cao, J., O'Day, D. R., Pliner, H. A., … Shendure, J. (2020). A human cell atlas of fetal chromatin accessibility. Science, 370(6518), eaba7612. doi: 10.1126/science.aba7612
- Dominguez, C. X., Müller, S., Keerthivasan, S., Koeppen, H., Hung, J., Gierke, S., … Turley, S. J. (2020). Single-cell RNA sequencing reveals stromal evolution into LRRC15+ myofibroblasts as a determinant of patient response to cancer immunotherapy. Cancer Discovery, 10(2), 232–253. doi: 10.1158/2159-8290.CD-19-0644
- Dong, J., Hu, Y., Fan, X., Wu, X., Mao, Y., Hu, B., … Tang, F. (2018). Single-cell RNA-seq analysis unveils a prevalent epithelial/mesenchymal hybrid state during mouse organogenesis. Genome Biology, 19(1), 31. doi: 10.1186/s13059-018-1416-2
- Dorrity, M. W., Alexandre, C. M., Hamm, M. O., Vigil, A.-L., Fields, S., Queitsch, C., & Cuperus, J. T. (2021). The regulatory landscape of Arabidopsis thaliana roots at single-cell resolution. Nature Communications, 12(1), 3334. doi: 10.1038/s41467-021-23675-y
- Drokhlyansky, E., Smillie, C. S., Van Wittenberghe, N., Ericsson, M., Griffin, G. K., Eraslan, G., … Regev, A. (2020). The human and mouse enteric nervous system at single-cell resolution. Cell, 182(6), 1606–1622.e23. doi: 10.1016/j.cell.2020.08.003
- Eberwine, J., Yeh, H., Miyashiro, K., Cao, Y., Nair, S., Finnell, R., … Coleman, P. (1992). Analysis of gene expression in single live neurons. Proceedings of the National Academy of Sciences of the United States of America, 89(7), 3010–3014. doi: 10.1073/pnas.89.7.3010
- Elyada, E., Bolisetty, M., Laise, P., Flynn, W. F., Courtois, E. T., Burkhart, R. A., … Tuveson, D. A. (2019). Cross-species single-cell analysis of pancreatic ductal adenocarcinoma reveals antigen-presenting cancer-associated fibroblasts. Cancer Discovery, 9(8), 1102–1123. doi: 10.1158/2159-8290.CD-19-0094
- Eraslan, G., Drokhlyansky, E., Anand, S., Subramanian, A., Fiskin, E., Slyper, M., … Regev, A. (2022). Single-nucleus cross-tissue molecular reference maps to decipher disease gene function. Science, 376(6594), doi: 10.1126/science.abl4290
- Fadok, V. A., Savill, J. S., Haslett, C., Bratton, D. L., Doherty, D. E., Campbell, P. A., & Henson, P. M. (1992). Different populations of macrophages use either the vitronectin receptor or the phosphatidylserine receptor to recognize and remove apoptotic cells. Journal of Immunology, 149(12), 4029–4035.
- Fan, H. C., Fu, G. K., & Fodor, S. P. A. (2015). Combinatorial labeling of single cells for gene expression cytometry. Science, 347(6222), 1258367. doi: 10.1126/science.1258367
- Fan, X., Tang, D., Liao, Y., Li, P., Zhang, Y., Wang, M., … Tang, F. (2020). Single-cell RNA-seq analysis of mouse preimplantation embryos by third-generation sequencing. PLoS Biology, 18(12), e3001017. doi: 10.1371/journal.pbio.3001017
- Fang, R., Preissl, S., Li, Y., Hou, X., Lucero, J., Wang, X., … Ren, B. (2021). Comprehensive analysis of single cell ATAC-seq data with SnapATAC. Nature Communications, 12(1), 1337. doi: 10.1038/s41467-021-21583-9
- Fischer, B., Meier, A., Dehne, A., Salhotra, A., Tran, T. A., Neumann, S., … Gentile, L. (2018). A complete workflow for the differentiation and the dissociation of hiPSC-derived cardiospheres. Stem Cell Research, 32, 65–72. doi: 10.1016/j.scr.2018.08.015
- Fleming, S. J., Marioni, J. C., & Babadi, M. (2019). CellBender remove-background: A deep generative model for unsupervised removal of background noise from scRNA-seq datasets. doi: 10.1101/791699
- Frantz, C., Stewart, K. M., & Weaver, V. M. (2010). The extracellular matrix at a glance. Journal of Cell Science, 123(Pt 24), 4195–4200. doi: 10.1242/jcs.023820
- Fu, G. K., Hu, J., Wang, P.-H., & Fodor, S. P. A. (2011). Counting individual DNA molecules by the stochastic attachment of diverse labels. Proceedings of the National Academy of Sciences of the United States of America, 108(22), 9026–9031. doi: 10.1073/pnas.1017621108
- Fu, Y., Wu, P.-H., Beane, T., Zamore, P. D., & Weng, Z. (2018). Elimination of PCR duplicates in RNA-seq and small RNA-seq using unique molecular identifiers. BMC Genomics, 19(1), 531. doi: 10.1186/s12864-018-4933-1
- Fujiwara, S., Baek, S., Varticovski, L., Kim, S., & Hager, G. L. (2019). High quality ATAC-Seq data recovered from cryopreserved breast cell lines and tissue. Scientific Reports, 9(1), 516. doi: 10.1038/s41598-018-36927-7
- Granja, J. M., Klemm, S., McGinnis, L. M., Kathiria, A. S., Mezger, A., Corces, M. R., … Greenleaf, W. J. (2019). Single-cell multiomic analysis identifies regulatory programs in mixed-phenotype acute leukemia. Nature Biotechnology, 37(12), 1458–1465. doi: 10.1038/s41587-019-0332-7
- Guillaumet-Adkins, A., Rodríguez-Esteban, G., Mereu, E., Mendez-Lago, M., Jaitin, D. A., Villanueva, A., … Heyn, H. (2017). Single-cell transcriptome conservation in cryopreserved cells and tissues. Genome Biology, 18(1), 45. doi: 10.1186/s13059-017-1171-9
- Guldner, I. H., Golomb, S. M., Wang, Q., Wang, E., & Zhang, S. (2021). Isolation of mouse brain-infiltrating leukocytes for single cell profiling of epitopes and transcriptomes. STAR Protocols, 2(2), 100537. doi: 10.1016/j.xpro.2021.100537
- Gupta, I., Collier, P. G., Haase, B., Mahfouz, A., Joglekar, A., Floyd, T., … Tilgner, H. U. (2018). Single-cell isoform RNA sequencing characterizes isoforms in thousands of cerebellar cells. Nature Biotechnology, 36(12), 1197–1202. doi: 10.1038/nbt.4259
- Habib, N., Avraham-Davidi, I., Basu, A., Burks, T., Shekhar, K., Hofree, M., … Regev, A. (2017). Massively parallel single-nucleus RNA-seq with DroNc-seq. Nature Methods, 14(10), 955–958. doi: 10.1038/nmeth.4407
- Hafemeister, C., & Satija, R. (2019). Normalization and variance stabilization of single-cell RNA-seq data using regularized negative binomial regression. Genome Biology, 20(1), 296. doi: 10.1186/s13059-019-1874-1
- Han, X., Wang, R., Zhou, Y., Fei, L., Sun, H., Lai, S., … Guo, G. (2018). Mapping the mouse cell atlas by Microwell-Seq. Cell, 172(5), 1091–1107.e17. doi: 10.1016/j.cell.2018.02.001
- Hanamsagar, R., Reizis, T., Chamberlain, M., Marcus, R., Nestle, F. O., de Rinaldis, E., & Savova, V. (2020). An optimized workflow for single-cell transcriptomics and repertoire profiling of purified lymphocytes from clinical samples. Scientific Reports, 10(1), 2219. doi: 10.1038/s41598-020-58939-y
- Heaton, H., Talman, A. M., Knights, A., Imaz, M., Gaffney, D. J., Durbin, R., … Lawniczak, M. K. N. (2020). Souporcell: Robust clustering of single-cell RNA-seq data by genotype without reference genotypes. Nature Methods, 17(6), 615–620. doi: 10.1038/s41592-020-0820-1
- Huang, Y., McCarthy, D. J., & Stegle, O. (2019). Vireo: Bayesian demultiplexing of pooled single-cell RNA-seq data without genotype reference. Genome Biology, 20(1), 273. doi: 10.1186/s13059-019-1865-2
- Jariani, A., Vermeersch, L., Cerulus, B., Perez-Samper, G., Voordeckers, K., Van Brussel, T., … Verstrepen, K. J. (2020). A new protocol for single-cell RNA-seq reveals stochastic gene expression during lag phase in budding yeast. ELife, 9, e55320. doi: 10.7554/eLife.55320
- Jean-Baptiste, K., McFaline-Figueroa, J. L., Alexandre, C. M., Dorrity, M. W., Saunders, L., Bubb, K. L., … Cuperus, J. T. (2019). Dynamics of Gene expression in single root cells of Arabidopsis thaliana. The Plant Cell, 31(5), 993–1011. doi: 10.1105/tpc.18.00785
- Kang, H. M., Subramaniam, M., Targ, S., Nguyen, M., Maliskova, L., McCarthy, E., … Ye, C. J. (2018). Multiplexed droplet single-cell RNA-sequencing using natural genetic variation. Nature Biotechnology, 36(1), 89–94. doi: 10.1038/nbt.4042
- Kanton, S., Boyle, M. J., He, Z., Santel, M., Weigert, A., Sanchís-Calleja, F., … Camp, J. G. (2019). Organoid single-cell genomic atlas uncovers human-specific features of brain development. Nature, 574(7778), 418–422. doi: 10.1038/s41586-019-1654-9
- Kaplan, N., Wang, J., Wray, B., Patel, P., Yang, W., Peng, H., & Lavker, R. M. (2019). Single-cell RNA transcriptome helps define the limbal/corneal epithelial stem/early transit amplifying cells and how autophagy affects this population. Investigative Ophthalmology & Visual Science, 60(10), 3570–3583. doi: 10.1167/iovs.19-27656
- Katzenelenbogen, Y., Sheban, F., Yalin, A., Yofe, I., Svetlichnyy, D., Jaitin, D. A., … Amit, I. (2020). Coupled scRNA-Seq and Intracellular Protein Activity Reveal an Immunosuppressive Role of TREM2 in Cancer. Cell, 182(4), 872–885.e19. doi: 10.1016/j.cell.2020.06.032
- Koopman, G., Reutelingsperger, C., Kuijten, G., Keehnen, R., Pals, S., & van Oers, M. (1994). Annexin V for flow cytometric detection of phosphatidylserine expression on B cells undergoing apoptosis. Blood, 84(5), 1415–1420. doi: 10.1182/blood.V84.5.1415.1415
- Krishnaswami, S. R., Grindberg, R. V., Novotny, M., Venepally, P., Lacar, B., Bhutani, K., … Lasken, R. S. (2016). Using single nuclei for RNA-seq to capture the transcriptome of postmortem neurons. Nature Protocols, 11(3), 499–524. doi: 10.1038/nprot.2016.015
- Lake, B. B., Chen, S., Sos, B. C., Fan, J., Kaeser, G. E., Yung, Y. C., … Zhang, K. (2018). Integrative single-cell analysis of transcriptional and epigenetic states in the human adult brain. Nature Biotechnology, 36(1), 70–80. doi: 10.1038/nbt.4038
- Lebrigand, K., Magnone, V., Barbry, P., & Waldmann, R. (2020). High throughput error corrected Nanopore single cell transcriptome sequencing. Nature Communications, 11(1), 4025. doi: 10.1038/s41467-020-17800-6
- Lee, S. K. (2018). Sex as an important biological variable in biomedical research. BMB Reports, 51(4), 167–173. doi: 10.5483/BMBRep.2018.51.4.034
- Levy, D., & Wigler, M. (2014). Facilitated sequence counting and assembly by template mutagenesis. Proceedings of the National Academy of Sciences of the United States of America, 111(43), E4632–E4637. doi: 10.1073/pnas.1416204111
- Li, H., Janssens, J., Waegeneer, M. D., Kolluru, S. S., Davie, K., Gardeux, V., … Aerts, S. (2021). Fly cell atlas: A single-cell transcriptomic atlas of the adult fruit fly. doi: 10.1101/2021.07.04.451050
- Li, S., Kendall, J., Park, S., Wang, Z., Alexander, J., Moffitt, A., … Wigler, M. (2020). Copolymerization of single-cell nucleic acids into balls of acrylamide gel. Genome Research, 30(1), 49–61. doi: 10.1101/gr.253047.119
- Lim, B., Lin, Y., & Navin, N. (2020). Advancing cancer research and medicine with single-cell genomics. Cancer Cell, 37(4), 456–470. doi: 10.1016/j.ccell.2020.03.008
- Long, Y., Liu, Z., Jia, J., Mo, W., Fang, L., Lu, D., … Zhai, J. (2021). FlsnRNA-seq: Protoplasting-free full-length single-nucleus RNA profiling in plants. Genome Biology, 22(1), 66. doi: 10.1186/s13059-021-02288-0
- Lopez-Anido, C. B., Vatén, A., Smoot, N. K., Sharma, N., Guo, V., Gong, Y., … Bergmann, D. C. (2021). Single-cell resolution of lineage trajectories in the Arabidopsis stomatal lineage and developing leaf. Developmental Cell, 56(7), 1043–1055.e4. doi: 10.1016/j.devcel.2021.03.014
- Lopes-Ramos, C. M., Chen, C.-Y., Kuijjer, M. L., Paulson, J. N., Sonawane, A. R., Fagny, M., … DeMeo, D. L. (2020). Sex differences in gene expression and regulatory networks across 29 human tissues. Cell Reports, 31(12), 107795. doi: 10.1016/j.celrep.2020.107795
- Love, M. I., Huber, W., & Anders, S. (2014). Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2. Genome Biology, 15(12), 550. doi: 10.1186/s13059-014-0550-8
- Ma, S., Zhang, B., LaFave, L. M., Earl, A. S., Chiang, Z., Hu, Y., … Buenrostro, J. D. (2020). Chromatin potential identified by shared single-cell profiling of RNA and chromatin. Cell, 183(4), 1103–1116.e20. doi: 10.1016/j.cell.2020.09.056
- Machado, L., Relaix, F., & Mourikis, P. (2021). Stress relief: Emerging methods to mitigate dissociation-induced artefacts. Trends in Cell Biology, 31(11), 888–897. doi: 10.1016/j.tcb.2021.05.004
- Macosko, E. Z., Basu, A., Satija, R., Nemesh, J., Shekhar, K., Goldman, M., … McCarroll, S. A. (2015). Highly parallel genome-wide expression profiling of individual cells using nanoliter droplets. Cell, 161(5), 1202–1214. doi: 10.1016/j.cell.2015.05.002
- Madissoon, E., Wilbrey-Clark, A., Miragaia, R. J., Saeb-Parsy, K., Mahbubani, K. T., Georgakopoulos, N., … Meyer, K. B. (2019). ScRNA-seq assessment of the human lung, spleen, and esophagus tissue stability after cold preservation. Genome Biology, 21, 1. doi: 10.1186/s13059-019-1906-x
- Maitra, M., Nagy, C., Chawla, A., Wang, Y. C., Nascimento, C., Suderman, M., … Turecki, G. (2021). Extraction of nuclei from archived postmortem tissues for single-nucleus sequencing applications. Nature Protocols, 16(6), 2788–2801. doi: 10.1038/s41596-021-00514-4
- Marand, A. P., Chen, Z., Gallavotti, A., & Schmitz, R. J. (2021). A cis-regulatory atlas in maize at single-cell resolution. Cell, 184(11), 3041–3055.e21. doi: 10.1016/j.cell.2021.04.014
- Mascotti, K., McCullough, J., & Burger, S. R. (2000). HPC viability measurement: Trypan blue versus acridine orange and propidium iodide. Transfusion, 40(6), 693–696. doi: 10.1046/j.1537-2995.2000.40060693.x
- McGinnis, C. S., Patterson, D. M., Winkler, J., Conrad, D. N., Hein, M. Y., Srivastava, V., … Gartner, Z. J. (2019). MULTI-seq: Sample multiplexing for single-cell RNA sequencing using lipid-tagged indices. Nature Methods, 16(7), 619–626. doi: 10.1038/s41592-019-0433-8
- Melms, J. C., Biermann, J., Huang, H., Wang, Y., Nair, A., Tagore, S., … Izar, B. (2021). A molecular single-cell lung atlas of lethal COVID-19. Nature, 595(7865), 114–119. doi: 10.1038/s41586-021-03569-1
- Mereu, E., Lafzi, A., Moutinho, C., Ziegenhain, C., McCarthy, D. J., Álvarez-Varela, A., … Heyn, H. (2020). Benchmarking single-cell RNA-sequencing protocols for cell atlas projects. Nature Biotechnology, 38(6), 747–755. doi: 10.1038/s41587-020-0469-4
- Mimitou, E. P., Lareau, C. A., Chen, K. Y., Zorzetto-Fernandes, A. L., Hao, Y., Takeshima, Y., … Smibert, P. (2021). Scalable, multimodal profiling of chromatin accessibility, gene expression and protein levels in single cells. Nature Biotechnology, 39(10), 1246–1258. doi: 10.1038/s41587-021-00927-2
- Minussi, D. C., Nicholson, M. D., Ye, H., Davis, A., Wang, K., Baker, T., … Navin, N. E. (2021). Breast tumours maintain a reservoir of subclonal diversity during expansion. Nature, 592(7853), 302–308. doi: 10.1038/s41586-021-03357-x
- Morsey, B., Niu, M., Dyavar, S. R., Fletcher, C. V., Lamberty, B. G., Emanuel, K., … Fox, H. S. (2021). Cryopreservation of microglia enables single-cell RNA sequencing with minimal effects on disease-related gene expression patterns. IScience, 24(4), 102357. doi: 10.1016/j.isci.2021.102357
- Nadelmann, E. R., Gorham, J. M., Reichart, D., Delaughter, D. M., Wakimoto, H., Lindberg, E. L., … Seidman, J. G. (2021). Isolation of nuclei from mammalian cells and tissues for single-nucleus molecular profiling. Current Protocols, 1(5), e132. doi: 10.1002/cpz1.132
- Navin, N., Kendall, J., Troge, J., Andrews, P., Rodgers, L., McIndoo, J., … Wigler, M. (2011). Tumour evolution inferred by single-cell sequencing. Nature, 472(7341), 90–94. doi: 10.1038/nature09807
- Noland, T. L., & Mohammed, G. H. (1997). Fluorescein diacetate as a viability stain for tree roots and seeds. New Forests, 14(3), 221–232. doi: 10.1023/A:1006561829931
- Nott, A., Schlachetzki, J. C. M., Fixsen, B. R., & Glass, C. K. (2021). Nuclei isolation of multiple brain cell types for omics interrogation. Nature Protocols, 16(3), 1629–1646. doi: 10.1038/s41596-020-00472-3
- O'Flanagan, C. H., Campbell, K. R., Zhang, A. W., Kabeer, F., Lim, J. L. P., Biele, J., … Aparicio, S. (2019). Dissociation of solid tumor tissues with cold active protease for single-cell RNA-seq minimizes conserved collagenase-associated stress responses. Genome Biology, 20(1), 210. doi: 10.1186/s13059-019-1830-0
- Pavel, A., Sandra, L., Jaroslav, T., Mikael, K., & Radek, S. (2019). Preparation of single-cell suspension from mouse breast cancer focusing on preservation of original cell state information and cell type composition. doi: 10.1101/824714
- Pei, W., Shang, F., Wang, X., Fanti, A.-K., Greco, A., Busch, K., … Rodewald, H.-R. (2020). Resolving fates and single-cell transcriptomes of hematopoietic stem cell clones by PolyloxExpress barcoding. Cell Stem Cell, 27(3), 383–395.e8. doi: 10.1016/j.stem.2020.07.018
- Pennartz, S., Reiss, S., Biloune, R., Hasselmann, D., & Bosio, A. (2009). Generation of single-cell suspensions from mouse neural tissue. Journal of Visualized Experiments, JoVE, (29), e1267. doi: 10.3791/1267
- Peterson, V. M., Zhang, K. X., Kumar, N., Wong, J., Li, L., Wilson, D. C., … Klappenbach, J. A. (2017). Multiplexed quantification of proteins and transcripts in single cells. Nature Biotechnology, 35(10), 936–939. doi: 10.1038/nbt.3973
- Phan, H. V., van Gent, M., Drayman, N., Basu, A., Gack, M. U., & Tay, S. (2021). High-throughput RNA sequencing of paraformaldehyde-fixed single cells. Nature Communications, 12(1), 5636. doi: 10.1038/s41467-021-25871-2
- Picelli, S., Faridani, O. R., Björklund, Å. K., Winberg, G., Sagasser, S., & Sandberg, R. (2014). Full-length RNA-seq from single cells using Smart-seq2. Nature Protocols, 9(1), 171–181. doi: 10.1038/nprot.2014.006
- Potter, A. S., & Steven Potter, S. (2019). Dissociation of tissues for single-cell analysis. Methods in Molecular Biology, 1926, 55–62. doi: 10.1007/978-1-4939-9021-4_5
- Qi, X., Yu, Y., Sun, R., Huang, J., Liu, L., Yang, Y., … Sun, B. (2021). Identification and characterization of neutrophil heterogeneity in sepsis. Critical Care, 25(1), 50. doi: 10.1186/s13054-021-03481-0
- Regev, A., Teichmann, S. A., Lander, E. S., Amit, I., Benoist, C., Birney, E., … Human Cell Atlas Meeting Participants. (2017). The human cell atlas. ELife, 6, e27041. doi: 10.7554/eLife.27041
- Reichard, A., & Asosingh, K. (2019). Best practices for preparing a single cell suspension from solid tissues for flow cytometry. Cytometry. Part A: The Journal of the International Society for Analytical Cytology, 95(2), 219–226. doi: 10.1002/cyto.a.23690
- Replogle, J. M., Norman, T. M., Xu, A., Hussmann, J. A., Chen, J., Cogan, J. Z., … Adamson, B. (2020). Combinatorial single-cell CRISPR screens by direct guide RNA capture and targeted sequencing. Nature Biotechnology, 38(8), 954–961. doi: 10.1038/s41587-020-0470-y
- Robinson, M. D., McCarthy, D. J., & Smyth, G. K. (2010). edgeR: A bioconductor package for differential expression analysis of digital gene expression data. Bioinformatics, 26(1), 139–140. doi: 10.1093/bioinformatics/btp616
- Rocks, D., Jaric, I., Tesfa, L., Greally, J. M., Suzuki, M., & Kundakovic, M. (2021). Cell type-specific chromatin accessibility analysis in the mouse and human brain. Epigenetics, 17(2), 202–219. doi: 10.1080/15592294.2021.1896983
- Rogozhnikov, A., Ramkumar, P., Shah, K., Bedi, R., Kato, S., & Escola, G. S. (2021). Demuxalot: Scaled up genetic demultiplexing for single-cell sequencing. doi: 10.1101/2021.05.22.443646
- Rosenberg, A. B., Roco, C. M., Muscat, R. A., Kuchina, A., Sample, P., Yao, Z., … Seelig, G. (2018). Single-cell profiling of the developing mouse brain and spinal cord with split-pool barcoding. Science, 360(6385), 176–182. doi: 10.1126/science.aam8999
- Russell, A. B., Elshina, E., Kowalsky, J. R., te Velthuis, A. J. W., & Bloom, J. D. (2019). Single-cell virus sequencing of influenza infections that trigger innate immunity. Journal of Virology, 93(14), doi: 10.1128/JVI.00500-19
- Ryu, K. H., Huang, L., Kang, H. M., & Schiefelbein, J. (2019). Single-cell RNA sequencing resolves molecular relationships among individual plant cells. Plant Physiology, 179(4), 1444–1456. doi: 10.1104/pp.18.01482
- Sahlin, K., & Medvedev, P. (2021). Error correction enables use of Oxford Nanopore technology for reference-free transcriptome analysis. Nature Communications, 12(1), 2. doi: 10.1038/s41467-020-20340-8
- Santos, M. D., Gioftsidi, S., Backer, S., Machado, L., Relaix, F., Maire, P., & Mourikis, P. (2021). Extraction and sequencing of single nuclei from murine skeletal muscles. STAR Protocols, 2(3), 100694. doi: 10.1016/j.xpro.2021.100694
- Sasagawa, Y., Danno, H., Takada, H., Ebisawa, M., Tanaka, K., Hayashi, T., … Nikaido, I. (2018). Quartz-Seq2: A high-throughput single-cell RNA-sequencing method that effectively uses limited sequence reads. Genome Biology, 19(1), 29. doi: 10.1186/s13059-018-1407-3
- Schmid, K. T., Höllbacher, B., Cruceanu, C., Böttcher, A., Lickert, H., Binder, E. B., … Heinig, M. (2021). ScPower accelerates and optimizes the design of multi-sample single cell transcriptomic studies. Nature Communications, 12(1), 6625. doi: 10.1038/s41467-021-26779-7
- Sheridan, B. S., & Lefrançois, L. (2012). Isolation of mouse lymphocytes from small intestine tissues. Current Protocols in Immunology, 99(1), 3.19.1–3.19.11. doi: 10.1002/0471142735.im0319s99
- Singh, M., Al-Eryani, G., Carswell, S., Ferguson, J. M., Blackburn, J., Barton, K., … Swarbrick, A. (2019). High-throughput targeted long-read single cell sequencing reveals the clonal and transcriptional landscape of lymphocytes. Nature Communications, 10(1), 3120. doi: 10.1038/s41467-019-11049-4
- Slyper, M., Porter, C. B. M., Ashenberg, O., Waldman, J., Drokhlyansky, E., Wakiro, I., … Regev, A. (2020). A single-cell and single-nucleus RNA-Seq toolbox for fresh and frozen human tumors. Nature Medicine, 26(5), 792–802. doi: 10.1038/s41591-020-0844-1
- Spaethling, J. M., Na, Y.-J., Lee, J., Ulyanova, A. V., Baltuch, G. H., Bell, T. J., … Eberwine, J. H. (2017). Primary cell culture of live neurosurgically resected aged adult human brain cells and single cell transcriptomics. Cell Reports, 18(3), 791–803. doi: 10.1016/j.celrep.2016.12.066
- Squair, J. W., Gautier, M., Kathe, C., Anderson, M. A., James, N. D., Hutson, T. H., … Courtine, G. (2021). Confronting false discoveries in single-cell differential expression. Nature Communications, 12(1), 5692. doi: 10.1038/s41467-021-25960-2
- Stenn, K. S., Link, R., Moellmann, G., Madri, J., & Kuklinska, E. (1989). Dispase, a neutral protease from Bacillus polymyxa, is a powerful fibronectinase and type IV collagenase. The Journal of Investigative Dermatology, 93(2), 287–290. doi: 10.1111/1523-1747.ep12277593
- Stoeckius, M., Hafemeister, C., Stephenson, W., Houck-Loomis, B., Chattopadhyay, P. K., Swerdlow, H., … Smibert, P. (2017). Simultaneous epitope and transcriptome measurement in single cells. Nature Methods, 14(9), 865–868. doi: 10.1038/nmeth.4380
- Stoeckius, M., Zheng, S., Houck-Loomis, B., Hao, S., Yeung, B. Z., Mauck, W. M., … Satija, R. (2018). Cell hashing with barcoded antibodies enables multiplexing and doublet detection for single cell genomics. Genome Biology, 19(1), 224. doi: 10.1186/s13059-018-1603-1
- Su, K., Wu, Z., & Wu, H. (2020). Simulation, power evaluation and sample size recommendation for single-cell RNA-seq. Bioinformatics, 36(19), 4860–4868. doi: 10.1093/bioinformatics/btaa607
- Sun, T., Song, D., Li, W. V., & Li, J. J. (2021). scDesign2: A transparent simulator that generates high-fidelity single-cell gene expression count data with gene correlations captured. Genome Biology, 22(1), 163. doi: 10.1186/s13059-021-02367-2
- Svensson, V., Beltrame, E., da, V., & Pachter, L. (2019). Quantifying the tradeoff between sequencing depth and cell number in single-cell RNA-seq. doi: 10.1101/762773
- Swann, J. C., Reynolds, J. J., & Galloway, W. A. (1981). Zinc metalloenzyme properties of active and latent collagenase from rabbit bone. Biochemical Journal, 195(1), 41–49. doi: 10.1042/bj1950041
- Swanson, E., Lord, C., Reading, J., Heubeck, A. T., Genge, P. C., Thomson, Z., … Skene, P. J. (2021). Simultaneous trimodal single-cell measurement of transcripts, epitopes, and chromatin accessibility using TEA-seq. ELife, 10, e63632. doi: 10.7554/eLife.63632
- Tabula Muris Consortium. (2020). A single-cell transcriptomic atlas characterizes ageing tissues in the mouse. Nature, 583(7817), 590–595. doi: 10.1038/s41586-020-2496-1
- Tabula Muris Consortium, Overall coordination, Logistical coordination, Organ collection and processing, Library preparation and sequencing, Computational data analysis, … Principal investigators. (2018). Single-cell transcriptomics of 20 mouse organs creates a Tabula Muris. Nature, 562, 367–372. doi: 10.1038/s41586-018-0590-4
- Tanay, A., & Regev, A. (2017). Single cell genomics: From phenomenology to mechanism. Nature, 541(7637), 331–338. doi: 10.1038/nature21350
- Tang, F., Barbacioru, C., Wang, Y., Nordman, E., Lee, C., Xu, N., … Surani, M. A. (2009). MRNA-Seq whole-transcriptome analysis of a single cell. Nature Methods, 6(5), 377–382. doi: 10.1038/nmeth.1315
- Tatsuoka, H., Sakamoto, S., Yabe, D., Kabai, R., Kato, U., Okumura, T., … Inagaki, N. (2020). Single-cell transcriptome analysis dissects the replicating process of pancreatic beta cells in partial pancreatectomy model. IScience, 23(12), 101774. doi: 10.1016/j.isci.2020.101774
- Tattikota, S. G., Cho, B., Liu, Y., Hu, Y., Barrera, V., Steinbaugh, M. J., … Perrimon, N. (2020). A single-cell survey of Drosophila blood. ELife, 9, e54818. doi: 10.7554/eLife.54818
- Thibivilliers, S., Anderson, D., & Libault, M. (2020). Isolation of plant root nuclei for single cell RNA sequencing. Current Protocols in Plant Biology, 5(4), e20120. doi: 10.1002/cppb.20120
- Thrupp, N., Sala Frigerio, C., Wolfs, L., Skene, N. G., Fattorelli, N., Poovathingal, S., … Fiers, M. (2020). Single-nucleus RNA-Seq is not suitable for detection of microglial activation genes in humans. Cell Reports, 32(13), 108189. doi: 10.1016/j.celrep.2020.108189
- Trevino, A. E., Müller, F., Andersen, J., Sundaram, L., Kathiria, A., Shcherbina, A., … Greenleaf, W. J. (2021). Chromatin and gene-regulatory dynamics of the developing human cerebral cortex at single-cell resolution. Cell, 184(19), 5053–5069.e23. doi: 10.1016/j.cell.2021.07.039
- Troiano, N. W., Ciovacco, W. A., & Kacena, M. A. (2009). The effects of fixation and dehydration on the histological quality of undecalcified murine bone specimens embedded in methylmethacrylate. Journal of Histotechnology, 32(1), 27–31. doi: 10.1179/his.2009.32.1.27
- Tsuji, K., Ojima, M., Otabe, K., Horie, M., Koga, H., Sekiya, I., & Muneta, T. (2017). Effects of different cell-detaching methods on the viability and cell surface antigen expression of synovial mesenchymal stem cells. Cell Transplantation, 26(6), 1089–1102. doi: 10.3727/096368917X694831
- Tung, P.-Y., Blischak, J. D., Hsiao, C. J., Knowles, D. A., Burnett, J. E., Pritchard, J. K., & Gilad, Y. (2017). Batch effects and the effective design of single-cell gene expression studies. Scientific Reports, 7, 39921. doi: 10.1038/srep39921
- van den Brink, S. C., Sage, F., Vértesy, Á., Spanjaard, B., Peterson-Maduro, J., Baron, C. S., … van Oudenaarden, A. (2017). Single-cell sequencing reveals dissociation-induced gene expression in tissue subpopulations. Nature Methods, 14(10), 935–936. doi: 10.1038/nmeth.4437
- Vieth, B., Ziegenhain, C., Parekh, S., Enard, W., & Hellmann, I. (2017). powsimR: Power analysis for bulk and single cell RNA-seq experiments. Bioinformatics, 33(21), 3486–3488. doi: 10.1093/bioinformatics/btx435
- Volovitz, I., Shapira, N., Ezer, H., Gafni, A., Lustgarten, M., Alter, T., … Ram, Z. (2016). A non-aggressive, highly efficient, enzymatic method for dissociation of human brain-tumors and brain-tissues to viable single-cells. BMC Neuroscience, 17(1), 30. doi: 10.1186/s12868-016-0262-y
- Waise, S., Parker, R., Rose-Zerilli, M. J. J., Layfield, D. M., Wood, O., West, J., … Hanley, C. J. (2019). An optimised tissue disaggregation and data processing pipeline for characterising fibroblast phenotypes using single-cell RNA sequencing. Scientific Reports, 9(1), 9580. doi: 10.1038/s41598-019-45842-4
- Wang, K., Xiao, Z., Yan, Y., Ye, R., Hu, M., Bai, S., … Navin, N. E. (2021). Simple oligonucleotide-based multiplexing of single-cell chromatin accessibility. Molecular Cell, 81(20), 4319–4332.e10. doi: 10.1016/j.molcel.2021.09.026
- Wang, Q., Xiong, H., Ai, S., Yu, X., Liu, Y., Zhang, J., & He, A. (2019). CoBATCH for high-throughput single-cell epigenomic profiling. Molecular Cell, 76(1), 206–216.e7. doi: 10.1016/j.molcel.2019.07.015
- Wang, W., Penland, L., Gokce, O., Croote, D., & Quake, S. R. (2018). High fidelity hypothermic preservation of primary tissues in organ transplant preservative for single cell transcriptome analysis. BMC Genomics, 19, 140. doi: 10.1186/s12864-018-4512-5
- Welch, J. D., Kozareva, V., Ferreira, A., Vanderburg, C., Martin, C., & Macosko, E. Z. (2019). Single-cell multi-omic integration compares and contrasts features of brain cell identity. Cell, 177(7), 1873–1887.e17. doi: 10.1016/j.cell.2019.05.006
- Wohnhaas, C. T., Leparc, G. G., Fernandez-Albert, F., Kind, D., Gantner, F., Viollet, C., … Baum, P. (2019). DMSO cryopreservation is the method of choice to preserve cells for droplet-based single-cell RNA sequencing. Scientific Reports, 9(1), 10699. doi: 10.1038/s41598-019-46932-z
- Woitowich, N. C., Beery, A., & Woodruff, T. (2020). A 10-year follow-up study of sex inclusion in the biological sciences. ELife, 9, e56344. doi: 10.7554/eLife.56344
- Wu, H., Malone, A. F., Donnelly, E. L., Kirita, Y., Uchimura, K., Ramakrishnan, S. M., … Humphreys, B. D. (2018). Single-cell transcriptomics of a human kidney allograft biopsy specimen defines a diverse inflammatory response. Journal of the American Society of Nephrology: JASN, 29(8), 2069–2080. doi: 10.1681/ASN.2018020125
- Wu, S. Z., Roden, D. L., Al-Eryani, G., Bartonicek, N., Harvey, K., Cazet, A. S., … Swarbrick, A. (2021). Cryopreservation of human cancers conserves tumour heterogeneity for single-cell multi-omics analysis. Genome Medicine, 13(1), 1–17. doi: 10.1186/s13073-021-00885-z
- Xie, X., Shi, Q., Wu, P., Zhang, X., Kambara, H., Su, J., … Luo, H. R. (2020). Single-cell transcriptome profiling reveals neutrophil heterogeneity in homeostasis and infection. Nature Immunology, 21(9), 1119–1133. doi: 10.1038/s41590-020-0736-z
- Xu, J., Falconer, C., Nguyen, Q., Crawford, J., McKinnon, B. D., Mortlock, S., … Coin, L. J. M. (2019). Genotype-free demultiplexing of pooled single-cell RNA-seq. Genome Biology, 20(1), 290. doi: 10.1186/s13059-019-1852-7
- Xu, X., Crow, M., Rice, B. R., Li, F., Harris, B., Liu, L., … Jackson, D. (2021). Single-cell RNA sequencing of developing maize ears facilitates functional analysis and trait candidate gene discovery. Developmental Cell, 56(4), 557–568.e6. doi: 10.1016/j.devcel.2020.12.015
- Yamazaki, A., Shue, F., Yamazaki, Y., Martens, Y. A., Bu, G., & Liu, C.-C. (2021). Preparation of single cell suspensions enriched in mouse brain vascular cells for single-cell RNA sequencing. STAR Protocols, 2(3), 100715. doi: 10.1016/j.xpro.2021.100715
- Yang, S., Corbett, S. E., Koga, Y., Wang, Z., Johnson, W. E., Yajima, M., & Campbell, J. D. (2020). Decontamination of ambient RNA in single-cell RNA-seq with DecontX. Genome Biology, 21(1), 57. doi: 10.1186/s13059-020-1950-6
- You, M., Chen, L., Zhang, D., Zhao, P., Chen, Z., Qin, E.-Q., … Yang, P. (2021). Single-cell epigenomic landscape of peripheral immune cells reveals establishment of trained immunity in individuals convalescing from COVID-19. Nature Cell Biology, 23(6), 620–630. doi: 10.1038/s41556-021-00690-1
- Young, M. D., & Behjati, S. (2020). SoupX removes ambient RNA contamination from droplet-based single-cell RNA sequencing data. GigaScience, 9(12), 1–10. doi: 10.1093/gigascience/giaa151
- Zhang, K., Hocker, J. D., Miller, M., Hou, X., Chiou, J., Poirion, O. B., … Ren, B. (2021). A single-cell atlas of chromatin accessibility in the human genome. Cell, 184(24), 5985–6001.e19. doi: 10.1016/j.cell.2021.10.024
- Zhang, M. J., Ntranos, V., & Tse, D. (2020). Determining sequencing depth in a single-cell RNA-seq experiment. Nature Communications, 11(1), 774. doi: 10.1038/s41467-020-14482-y
- Zheng, Y.-F., Chen, Z.-C., Shi, Z.-X., Hu, K.-H., Zhong, J.-Y., Wang, C.-X., … Xiao, C.-L. (2020). HIT-scISOseq: High-throughput and high-accuracy single-cell full-length isoform sequencing for corneal epithelium. doi: 10.1101/2020.07.27.222349
INTERNET RESOURCES
- http://broadinstitute.github.io/picard/
- https://support.illumina.com/bulletins/2016/10/how-many-cycles-of-sbs-chemistry-are-in-my-kit.html
- https://kb.10/genomics.com/hc/en-us/articles/360027640311
- https://kb.10/genomics.com/hc/en-us/articles/360048826911
- https://assets.fishersci.com/TFS-Assets/LSG/Application-Notes/D19575.pdf
- https://www.protocols.io/view/Red-Blood-Cell-Lysis-Protocols-e3dbgi6
- https://support.illumina.com/bulletins/2016/10/how-many-cycles-of-sbs-chemistry-are-in-my-kit.html
Broad Institute. (version 2.27.1). “Picard Tools.” Broad Institute, GitHub repository.
How many cycles of SBS chemistry are in my kit? (n.d.).
kb.10×genomics.com - a. Can I sort nuclei for Single Cell ATAC sequencing or Single Cell Multiome ATAC + GEX? 10X Genomics, Inc.
kb.10×genomics.com - b. What are the best practices for flow sorting cells for 10× Genomics assays? 10X Genomics, Inc.
Kielberg, V. fishersci.com Thermo Fisher, Inc. (Updated 2010).
Miller, K. (2016). Red blood cell lysis protocols.
How many cycles of SBS chemistry are in my kit? Illumina, Inc. (Updated 2021 Mar 17).